NORTH CAROLINA, GEORGIA, AND MONTANA. 187 



According to them the northern system cut through the Blue 

 Eidge at right-angles, and then turn back on the opposite side 

 of the ridge. 



Now there is no such phenomena connected with these 

 outcrops. They evidently belong to separate systems. The 

 outcrops along the northern system occur at intervals ranging 

 from one to fifteen miles. The belt or zone along which these 

 outcrops occur never exceeds four miles in width on the north- 

 ern side of the ridge. On the opposite side the system is not 

 so well defined, and the outcrops are rarer. 



Upon these serpentine beds there exists chalcedony, chro- 

 mite on some of them, chlorite, talc, steatite, anthophyllite, tour- 

 maline, emerylite, epidote on some of them, zoisite, and albite, 

 with occasionally asbestus and picrolite, as also actinolite and 

 tremolite. The corundum at some places seems to occur mostly 

 in ripidolite in fissures of the serpentine. At Cullakenih the 

 corundum with its immediate associates is in chlorite, except 

 the red variety, which is in zoisite, containing a minute quantity 

 of chrome. 



Throughout all the range of rocks for the great extent re- 

 ferred to corundum forms a geognostic mark of this chrysolite- 

 rock just as it does of the calcareous rock bearing corundum 

 described by me in Asia Minor. They belong to the same 

 geological epoch, and overlie the gneiss, etc. 



The closest investigation shows that the chrysolite in North 

 Carolina takes the place of calc-rock in Asia Minor; that these 

 are invariably the gangue rock in the two different quarters 

 of the globe ; but, as remarked above, the contiguous rock 

 shows them both to be of the same geological period, over- 

 lying directly the primary rocks ; and both of them are also 

 identical geologically with the Chester emery formation of 

 Massachusetts. 



While all the localities of corundum and emery I have ex- 

 amined exhibit certain marked and prominent characteristics 

 common to them all, and evince unmistakable evidence of geo- 

 logical identity, yet each locality has its peculiar character- 

 istics. In all cases, however, the masses of corundum give 

 evidence of having been formed by a process of segregation, 

 as described in my memoir on the Asia Minor emery. 



In Asia Minor the Gumuch-dagh emery has but little black 



